Interpretation of Inelastic Light Scattering Measurements in 4He
We describe calculations of the inelastic light scattering spectrum for frequencies of the order of up to several times the roton frequency. The calculations are based on the two body approximation in a theoretical description of the fluid due to Pandiharipande and Manousakis. We use the results to determine the role of two mechanisms for the development of multiquasiparticle structure in the spectrum which we proposed earlier. We find that the mechanism arising from quasiparticle anharmonicities plays a much larger role in producing these structures in the spectrum than does the mechanism arising from nonlinearities in the relation between the density and quasiparticle operators. We find that the three quasiparticle couplings on which the theory rests depend strongly on the magnitudes and directions of the quasiparticles in a way which strongly favors processes involving colinear momenta. This has striking qualitative effects on the details of the predicted spectra.
KeywordsHelium Atom Quasi Particle Quasiparticle State Body Approximation Quasiparticle Spectrum
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- 2.J. W. Halley, Bull. Am. Phys. Soc. 13, 398 (1968)Google Scholar
- 7.J. W. Halley, in “Elementary Excitations in Quantum Fluids”, K. Ohbayashi and M. Watabe, eds., Springer-Verlag Series in Solid State Sciences 79, p. 106 (1989)Google Scholar
- 12.E.Manousakis and V. R. Pandharipande, Phys. Rev. B31, 7029 (1985); B33, 150 (1986)Google Scholar
- 19.J. W. Halley and M. S. Korth, unpublishedGoogle Scholar